JPH11314385A - Image recorder and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce energy required for image formation. SOLUTION: When an image is recorded on a thermal medium 255, the medium 255 is radiated from a single radiation transmitter 205 and a first part of the medium is heated up to a first temperature lower than a threshold recording level. The medium 255 is further radiated from same radiation transmitter 205 and other part of the medium 255 is heated up to a second temperature higher than the threshold level thus recording an image on the medium 255.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to recording images on a heat-sensitive medium,
More specifically, thermal recording technology (thermal
recording technique). The present technology is particularly suitable for an image setter and a plate setter.

[0002]

2. Description of the Related Art Thermal imaging involves irradiating a heat-sensitive medium with a laser beam or the like, causing a change in medium characteristics, and causing the medium temperature to exceed a threshold temperature at which either a positive or negative image can be recorded on the medium. It is widely known as an imaging method for increasing the image quality. As the heat-sensitive medium, for example, a metal or nonmetal material such as a polyester film or an aluminum plate material is used.

[0003] Thermal imaging is basically a threshold energy process.
ss). When sufficient energy is applied to the heat-sensitive medium, its characteristics change and dry or wet processing (dry processing) is performed.
The image is recorded on the media with or without wet processing. The process of thermal recording involves the transfer of non-metallic materials from metal ablation.
f non-metallic material), change of material phase (change of
phase of materials). But,
Regardless of the process used, the energy applied for recording must exceed the recording energy threshold of the medium on which the image is to be recorded.

[0004] Optical thermal imaging systems such as imagesetters and platesetters
In s), laser diodes or solid state lasers are usually used as radiation sources. Lasers generate and emit laser light, which is scanned over a thermal medium to record an image. The scanning speed and the laser output power are set to values at which sufficient energy is applied to the medium to raise the medium temperature above the threshold temperature for image recording. Therefore, the laser output power and the scanning speed of the image forming apparatus are usually determined in association with each other.

[0005] A commercially available prepress image forming apparatus (prepress image forming apparatus)
High power lasers are used in imaging systems.
By using these lasers, the imaging beam (imag
Even though the ingbeam is scanned over the medium at high speed, the laser light beam can be directed onto the medium for a time sufficient to raise the medium temperature above the threshold temperature required for image recording.

Various techniques have been proposed to reduce the source output power required to record an image on a thermal medium. For example, using a second light source to emit the portion of the medium that is to be varied, the medium may be pre-heated to some extent before applying another beam of radiation from a laser source to record an image on the medium. It is suggested that you keep it. However, these devices must scan the two sources in concert,
It is complicated. Furthermore, the cost of the extra radiation source and the cost of installing it during the production of the device is high, which increases the cost of the device. In reality, since the beams from the respective radiation sources cannot be perfectly matched, radiation loss occurs, and the total amount of energy actually required for recording exceeds the theoretical value of the energy level required for recording. In addition, the extra energy required to operate the second radiation source further increases the operating costs of the device.

[0007] Another proposed technique is to preheat a small portion of a medium, which causes a change, to a temperature lower than a recording temperature threshold, so that a small portion of a medium, which causes a change, is preheated. There is a method in which a desired image is recorded by applying an image forming beam to the entire portion of the medium that causes a change, including the portion to which the preheating beam is applied, after changing the optical characteristics of the medium. The small area where the preheating beam is applied completely overlaps the area where the beam is applied to form the desired image, so the small area that is altered by the preheating radiation beam is It does not affect the overall dimensions of the larger part of the area changed by the creation beam. This technology uses the modulation energy (mo
The amount of energy needed to create the image can be increased, but with the disadvantage of increasing the amount of energy required to create the image.

Therefore, there is a need for an image forming apparatus with low energy, high quality, and a single radiation source per pixel.

[0009]

OBJECTS OF THE INVENTION It is therefore an object of the present invention to reduce the amount of energy required to form an image on a thermal medium.

A further object of the present invention is to provide a low energy thermal image forming apparatus for forming a high quality image on a thermal medium.

Still another object of the present invention is to provide a low-cost thermal image forming apparatus for forming a high-quality image on a thermal medium.

[0012] Other objects, advantages and novel features of the invention will become apparent to those skilled in the art from the present disclosure, including the following detailed description, as well as from the practice of the invention. Hereinafter, the present invention will be described based on preferred embodiments, but it should be understood that the present invention is not limited thereto. It is recognized that those of ordinary skill in the art and who have access to the teachings of this document will have other embodiments, modifications, examples, and other uses that may be made. And the invention has significant utility thereto.

[0013]

SUMMARY OF THE INVENTION The present invention is directed to recording images on thermal media. The medium is a metallic or non-metallic medium, and the technology is equally applicable whether wet, dry or untreated.

According to the present invention, a medium, whether text or graphic, on which a positive or negative image is recorded, is radiated from a radiation emitter.
That is, radiation is performed on a portion of the medium where recording is performed, that is, a portion that changes due to heat and a portion where recording is not performed. The radiation may be in any form, for example a laser beam. Radiation transmitter (radiat
The ion emitter may be of virtually any type, for example, a laser source that produces and emits a laser beam, or an optical fiber end from which the laser beam is emitted.

The portion of the medium where no recording is to take place is irradiated with a radiation beam from the emitter at a first output.
The radiation beam preheats these portions of the medium to a temperature below a threshold temperature at which the medium undergoes a thermal change. In some but not all cases, it may be desirable to have the preheating temperature of the non-recording portion of the medium be just slightly lower than the recording temperature.

The portions of the medium where recording is to take place are subjected to a second, higher power radiation beam from the same light emitting device to raise the temperature of these media portions to a second temperature above the recording temperature threshold. increase. As a result, an image is recorded on the medium. Preferably, impinging on the medium (imping
e) the output of the radiation beam is a first mode that emits at a first output to a portion of the medium where no recording is to take place, and then a second mode that is different and preferably higher than the first output. At the output, the modulation output is varied using a modulator controlled by a controller to operate in two modes, a second mode that emits another portion of the image to form an image. Switch the second output level. Alternatively, a directly modulated laser source (directly mod
A modulated laser source, such as a laser diode or a laser diode array, may be used instead of a continuous waive laser source and a modulator. In addition, when using continuous light sources, modulation is performed using special light modulators or other mechanical or acoustic, electrical or optical modulation techniques.

Advantageously, the medium is continuously radiated from the radiation transmitter while the modulator is switched between the first and second modes of operation by the controller.
The continuously emitted radiation beam is thereby modulated in such a way that the first and second outputs are switched by the beam impinging on the medium. As a result, the radiation beam of the first output impinges on the unrecorded part of the medium and the second
Will impinge on the portion of the medium where recording is to take place.

Generally, the radiation is deflected onto the medium by an optical scanning device such as a spin mirror, prism, moving lens or other scanning element. The beam is scanned at the same speed, regardless of whether the medium is recorded or not recorded on the medium. If necessary, a controller can be used instead of a modulator to control the modulatable power source, such as a tunable laser, to change the radiation beam output between two modes of operation, non-recording and recording. it can. This is particularly advantageous for devices where multiple sources are used.

Using the present invention, a fine image (fine feature)
The total amount of power required to record an image) increases the media temperature to the recording temperature, that is, to a temperature equal to or higher than the recording temperature threshold, and the amount of power conventionally required to record an image on the media. The feature is that it is much less than the output. Thus, the present invention can be used to reduce the radiation output that had to be separately generated to record an image on a medium.

[0020]

1 and 2 show an optical path (opti).
1 shows an imaging device having a single output laser beam source 205 for generating and transmitting a laser beam along a cal path (250). The emitted laser light beam converges through condensing lens 210 before entering modulator 215. As the modulator 215, an acousto-optic modulator (acousto-
optics modulator (AOM), electro-optic modulator (elec)
tro-optics modulator (EOM), spatial light modulator (sp
Atomic light modulators (SLMs) and other types of modulators. The modulator 215 has the 2
Three output levels, the threshold recording output (thresh) required to thermally change the image to record it on the thermal medium 225
modulate the beam between higher and lower levels.

The laser light beam passes through the first and second condenser lenses 220 and 225 and is focused on the spin mirror 240 by the last condenser lens assembly 230. The spin mirror 240 determines the type of media, the available laser power, and the addressability of the device.
Rotate at a speed that is a function of The spin mirror 240 converts the laser light beam into an image plane of the thermal medium 255 (image pl).
ane) Deflected towards 245.

The modulator 215 includes a control panel 305 on which a keypad 320 and a display 330 are mounted.
Is controlled by the control device 300 including The control device 300 also includes a controller 310 having a communication port 340 for receiving input from a remote operator input device. If necessary, connect the communication port 340 to the controller 310.
Needless to say, the information may be used to transmit information from the vehicle to a remote driving position. To control the modulator 215, the controller 310
The signal is transmitted to the modulator 215 using 50. The controller can also transmit commands using another communication line (not shown) to transmit the laser 205 and the spin mirror 240.
Control. As described in more detail below, the controller includes a processor for causing the modulator 215 to generate a command signal in accordance with instructions programmed and stored in the controller 310.

The apparatus of FIGS. 1-2 operates as follows. For example, in response to operator instructions entered from keypad 320 and displayed on display 330, a signal is emitted from controller 310 to activate the device including laser 205, modulator 215 and spin mirror 240. . The laser 205 generates a radiation beam via a condenser lens and transmits the beam to the modulator.

A signal transmitted from the controller 310 to the modulator 215 via the communication line 350,
5, the modulator operates in the first mode according to the signal representing the part where no recording takes place.
By modulating the laser beam emitted from the laser 205, a part of the radiation beam emitted from the laser 205 is deflected.
The deflected portion of the beam is blocked inside the modulator 215 and is not output therefrom. This reduces the power of the radiation beam emitted from modulator 215 to less than the power required to record on the medium. Thus, the radiation beam output from the modulator 215 along the optical path 250 in the first mode of operation, referred to below as the unrecorded beam, is at a first output level that is insufficient for recording on the medium. . The non-recording beam is sent from the first and second condenser lenses and the last condenser lens assembly 230 to the spin mirror 240.

The spin mirror 240 deflects the non-recording beam so that an image plane 245 is formed on a portion where recording is not performed.
Is scanned. The output of the non-recording beam preheats the non-recording portion of the thermal medium 255 to a temperature lower than the threshold temperature at which the thermal medium 255 changes, with the non-recording beam impinging on the image plane 245.

If appropriate, the controller 310 of the control device 300 also communicates via a communication line 350 a second line representing the part on the image plane 245 where the recording is to take place.
Is generated and sent to the modulator 215. In response to this command, the modulator 215 switches to a second mode of operation with different modulation parameters and the laser 205
Modulates the laser light beam emanating from the laser light beam to a different, typically lower, portion of the laser light beam.
of the laser light beam). as a result,
Another portion of the beam radiation is blocked inside modulator 215, and the output radiation beam has a second output power that is different from and generally higher than the output power of the unrecorded beam. This recording beam travels along optical path 250 and
The light is output onto the spin mirror 240 through the condenser lenses 220 and 225 and the final condenser lens assembly 230.

The spin mirror 240 deflects the recording beam to scan an area of the image plane 245 where recording is to be performed. The output power of the recording beam is set to a value such that the beam hitting the image plane 245 heats the area of the thermal medium 255 where recording is performed to a temperature higher than the threshold temperature at which the thermal medium 255 thermally changes.

The controller 310 controls the laser 205
Controls the laser 205 to continuously generate and emit a beam of radiation, which is modulated by the modulator 215 between non-recording output power and recording output power in response to a signal from the controller 310. You.

It should be noted that although the spin mirror 240 can operate with different addressabilities and therefore has a variable speed, there is only one operating speed during modulation of the radiation beam by the modulator 215. . More specifically, in response to the input addressing capability, the controller 310 generates a scanning speed signal, which is sent to the spin mirror 240, where the rotation speed of the spin mirror determines the selected addressing capability and media type. Is set to the value corresponding to. Once the addressing capability is selected, the spin beam generated by the laser 205 is modulated between the non-recording output power and the recording output power according to a control signal sent over the communication line 350, while the spin beam is spinning. The mirror keeps the same speed.

Also, those skilled in the art will recognize that the modulator may be replaced by a modulatable laser source, such as a modulatable laser diode. In that sense, the modulatable laser source can be controlled by a controller and operated in the first and second modes to emit a laser light beam having a first output power and a second output power.

FIG. 1 shows the optical paths 250 ', 250 ", 25
An imaging device having multiple modulatable single output power sources 205 'for generating and transmitting a laser light beam along 0 "" is shown. The transmitted laser light beam is focused through condensing lenses 220 ', 225' before hitting the image surface 245 'of the thermal medium 255'. The modulated power sources 205 'each have two predetermined output powers, one higher and one lower than the threshold recording output power required for the thermal medium 255' to undergo a thermal change to record an image. Emit a beam that is modulated between levels.

The laser light beam passes through first and second condenser lenses 220 ′ and 225 ′, respectively, to the image plane 24.
It is 5 '. The spin mirror 240 rotates at a speed that is a function of the media type, available laser output power, and the addressability of the device. Spin mirror 240 deflects the laser light beam onto image plane 245 of thermal medium 255.

The modulatable radiation source 205 'is controlled by a control device 300' including a control panel 305 'with a keypad 320' and display 330 '. The control device 300 'also includes a controller 310' having a communication port 340 'capable of receiving input from a remote operator input device. It should be understood that the port 340 'can be used to transmit information from the controller 310' to a remote operating site if desired. In order to control the modulatable radiation source 205 ', the controller 310' generates a signal and the communication line 3 '
Transmit to the radiation source 205 'via 50'. As will be described in further detail below, the controller includes a programmed instruction stored in controller 310 '.
ed instructions)
nals) to the radiation source 205 '.

The image forming apparatus shown in FIG. 1 operates as follows. In response to operator instructions entered from the keypad 320 'and displayed on the display 330' if necessary, the controller 310 '
Generate signals to start the operation, including 5 '. Laser 205 'produces and modulates a beam of radiation and passes through condenser lenses 220', 225 'to image plane 245'.
Send to

Communication line 35 from controller 310 '
0 'to the radiation source 205'
According to the signal representing the area of the image plane 245 where no recording takes place, each of the radiation sources modulates the generated laser light beam 205 to deflect a portion of the radiation beam emitted by the laser 205 ′. It operates in the mode. The deflected part of each beam is laser 2
05 'is blocked inside and therefore not output here. This will reduce the output power of the radiation beam emitted from one or more lasers 205 'below the threshold output power required to record on the medium. The radiation beam output from the laser 205 'in the first mode of operation along the optical paths 250', 250 ", 250 '" will hereinafter be referred to as a non-recording beam, which is thus recorded on the medium. The non-recording beam is sent to the imaging plane 245 'through the first and second condenser lenses 220' and 225 ', which is insufficient to perform The area where no recording is to be performed is scanned, and the output power of the non-recording beam is set to the image plane 24.
The non-recording beam colliding with 5 ′ is set to a value that preheats the non-recording area of the thermal medium 255 ′ to a temperature lower than a threshold temperature at which the thermal medium 255 ′ changes.

If this is appropriate, the control device 3
00 ′ controller 310 ′ also has image plane 245 ′.
A second control command indicating an area in which recording is performed is generated and transmitted via the communication line 350 '. In response to this command, the radiation source switches to the second mode of operation and modulates the resulting laser light beam to deflect a different portion of the laser light beam, typically a lower power portion. As such, another portion of the beam radiation is blocked within radiation source 205 ', and the output radiation beam has a second output power that is different from and typically higher than the output power of the unrecorded beam. The recording beam is output along optical paths 250 ', 250 ", and 250'" and passes through first and second condenser lenses 220 'and 225' to scan an area of the image plane where recording is to be performed. The output power of the recording beam is such that the beam impinging on the image plane 245 'heats the area of the thermal medium 255' where recording is performed to a temperature above a threshold temperature at which the thermal medium 255 'thermally changes. Set to value.

The controller 310 'controls each laser 2
By controlling the operation of 05 ′, the laser 205 continuously generates and emits a radiation beam in response to a signal from the controller 310 between the non-recording output power and the recording output power.

FIG. 3 shows the control device 300 in a slightly simplified manner. Those skilled in the art will recognize that it is easy to modify control device 300 to perform the functions of control device 300 'described above. As shown in FIG. 3, the controller 310 includes a digital processor 510 and a display 430. The control device 300 may be assembled from commercially available hardware components or may be specially designed. One aspect of the uniqueness of the controller 310 is that the read only memory (ROM) 550
In the software instructions stored in.

In addition to processor 510 and ROM 550, controller 310 includes a communication interface 570 for communicating with modulator 215 via communication line 350.
including. The communication interface 570 is the communication port 34
0 to receive data from an operator input device at a remote location, and transmit data if necessary. Communication to the modulator 215 includes the indication signals necessary to instruct the modulator 215 to operate in the different modes of operation described above.

The input interface 520 provides an interface with the keypad 320, and the display interface 530 provides an interface with the display 330 of the control device 300. The random access memory (RAM) 560 is provided for temporarily storing data used by the processor 510 according to a programmed instruction of the controller 310. Bus 540 provides for the transfer of signals between the various subcomponents within controller 310 in a conventional manner. Processor 51
0 indicates to perform the operation described herein above,
Developing the programming instructions stored in ROM 550 is a routine programming effort and, needless to say, can be easily accomplished by those skilled in the art without the need for experimentation.

The operation of the control device 300 shown in FIG. 3 will be described with reference to the embodiment of FIG. Controller 3
The ten components interact in a conventional manner. Therefore, the routine operation of the illustrated components is not generally described because it is widely known to a skilled person.

To begin operation of the image forming apparatus of FIGS. 1-2, an image setter or platesetter operator enters the selected addressing capabilities of the apparatus and the type of media into keypad 320 of controller 300. This information is sent to processor 510 via input interface 520 and bus 540. Processor 510 generates a signal, which is sent to modulator 215 via communication link 350. In response to this signal, the portion of the laser beam that is deflected by modulator 215 in the first and second modes of operation is set by the modulator.

According to the image signal received by the control device 300, for example, via the port 340, the processor 510 connects the interface 570 with the communication line 3.
A signal is sent to modulator 215 via 50.
In accordance with these signals, the mode of operation of modulator 215 is switched to a mode corresponding to the imaging requirements. Processor 510 processes all received information according to unique programming instructions for controller 310 stored in ROM 550. These instructions are sent to or retrieved from the RAM 560 while the control device 300 is operating.

More specifically, the processor 510 includes:
A signal is generated according to the programmed instructions, which signal is transmitted via bus 540 to communication interface 570.
And sent to modulator 215 to control modulator 540 to modulate the radiation beam generated by laser 205. According to the control signal received from the controller 310, for example, the modulator 215 operating in the first mode emits a non-recording light beam having a first preset output power. This light beam is scanned on the heat-sensitive medium 255 by the spin mirror 240. The spin mirror 240 also operates according to a control signal from the controller 310 to scan a portion of the medium 255 where recording is not performed.

In accordance with the programming instructions stored in RAM 560, processor 510 generates another control signal, which is transmitted by communication interface 570 to communication line 350 to scan the portion of the medium on which recording is to be performed. To the modulator 215. In response to this signal, modulator 215 switches to its second mode of operation and modulates the light beam generated by laser 205 to emit a recording light beam having a second preset output power. The spin mirror scans the imaging beam above the image plane 245 of the thermal medium 255. As a result, the recording beam is scanned to record on another portion of the medium.

Processor 510 generates yet another signal in accordance with the programming instructions and switches the mode of operation of modulator 215 back to non-recording mode, for example, the next portion of imaging plane 245 where no recording takes place. Scan. Another control signal is generated,
The modulator 215 is switched back to the recording mode to record on another part of the medium. This control sequence
This continues until the desired image is recorded on the image plane of the thermal medium 255.

Those skilled in the art will recognize that the beam output power in each mode of operation may vary depending on the particular thermal medium on which the image is recorded,
It will be appreciated that the setting must be based on the desired resolution or addressability, the spot size of the laser, and the screening technique used. Careful selection of the operating parameters of the modulator 215 in each mode of operation allows the image to be optimized and produces high resolution, high quality images while at the same time requiring the overall output power of the imager. The amount can be reduced.

FIG. 4A shows the heat sensitive medium 255 described above.
The part that is not recorded and the part that is recorded are shown. As shown, the unrecorded area of the image plane 245, i.e., the area that does not include the portion where the letter A was recorded as a positive image, when the modulator 215 is operated by the controller 300 in the first mode of operation. Scanning is performed by a non-recording laser light beam transmitted from the modulator 215. More specifically, the non-recording area is scanned by the modulator 215 operating in the first mode, and is preheated to a temperature lower than the threshold recording temperature of the thermal medium 255. Image plane 2
45, that is, a portion of the medium where the character A is recorded as a positive image,
Is scanned by the modulator 215 controlled to operate in the second mode, and an image is recorded on the image plane 245 of the thermal medium 255.

FIG. 4B shows that the unrecorded portion of the image plane 245 is scanned with the non-recording light beam by controlling the modulator 215 to operate in the first mode by the control device 300, and the character A is converted into a negative image. make,
By controlling to operate in the second mode,
14 shows another example of the image creating apparatus in which the image is recorded on another portion of the image plane 245.

When the non-recording area of the medium 255 is heated by the non-image forming beam to a temperature just below the threshold recording temperature, the recording area of the medium is preheated to some extent. The amount of preheating, if any, depends on the heat transfer characteristics of the medium 255 and other factors, as will be appreciated by those skilled in the art. For example, the preheating temperature of a portion of the medium 255 where the image 510 of FIG. 4A is to be created is predetermined, and this information is used to set the radiant output power in the second operation mode, and the heat sensitive medium is set. It may be possible to record an image on the 255 image plane 245.

However, the non-recorded portion and the recorded portion of the medium usually have various sizes and positions. Therefore, the preheating of the recorded portion of the medium is often somewhat non-uniform. In such a case, the image plane 245 of the thermal medium 255 may be present when the modulator 215 is in the second mode of operation to record an image, even though the preheating effect may have been present.
Would have little effect in determining the minimum power required to apply the laser to the laser.

The desired positive or negative image small features are recorded on the medium using the dual mode of operation described above, whether or not the area of the medium 255 where the image is to be created is preheated. The total amount of energy required to do this is less than when using the prior art. However, despite these factors, a reduction in the total amount of energy required can be achieved using the above techniques.

FIG. 5 shows the range of radiation beam power levels, with single pixel horizontal and vertical lines.
vertical line) shows the change in exposure output power required to properly represent. More specifically, curves 110, 12
0 indicates the radiation beam output power for recording a 1 × 1 pixel line having a spot size of 18 μm, respectively.
Curve 110 represents the radiant power for recording a vertical line. Curve 120 represents the radiation power required to record a horizontal line with a spot size of 18 μm. Curves 130, 1
The curve 40 is the same as the curves 110 and 120 except that the spot size is as large as 22 μm. As is well understood by those skilled in the art, in most thermal recording devices, optimizing the recording parameters consists in setting the size of the recording spot. The pulse width is then adjusted to adjust the exposure response of the single pixel horizontal and vertical lines (exposure respo
nse). The curve shown in FIG. 5 represents 2400 dots per inch (dpi).

As can be seen from the curve 110, when a vertical line having a spot size of 18 μm is to be formed by using the conventional technique, the energy level of the recording beam is, in the case of the example shown in FIG. About 75 to 80 mj / cm ² , as indicated by the intersection of the axes. That is, this is the required amount of recording beam output power when there is no non-recording beam. According to the present invention, the recording beam output power required to obtain a single pixel vertical line is 55-60 m since the energy level of the non-recording beam applied to the medium is increased to about 15% of the recording beam output power.
j / cm ² .

When the non-recording beam output power increases to 15% or more of the recording beam output power, the corresponding decrease in the recording beam output power decreases. Therefore, when the output power of the non-recording beam is about 20% of the output power of the recording beam, an almost optimal balance between the output power of the non-recording beam and the output power of the recording beam can be obtained. A threshold of 20% is also advantageous for recording a single pixel horizontal line of 18 μm represented by curve 120 and horizontal and vertical lines of 22 μm represented by curves 130 and 140, as shown in FIG.

By operating the modulator 215 of FIG. 1 or by modulating the laser source of FIG. 1 in the dual mode as described above, as shown by the curves in FIG. Can be greatly reduced in the total amount of device output power required to record the power. For example, curve 11
Taking 0 as an example, the creation of a single pixel vertical line that typically requires a recording beam output power of 75 to 80 MJ / cm ² would require 55 to 60 mj / cm ² if the non-recording beam output power is 20%. The output of In that sense, the recording beam output power is 55 to 60 mj / cm ² , and the non-recording beam output power is 11 to 12 mj / cm ² . A line width match can generally be achieved at non-recording beam output power levels of 20% -30%.
If the output power of the non-recording beam is further increased, the part of the medium that has not been exposed starts to be noticeable (begi
n to mark). Because some thermal media have lower gradations than other media, the exact branch point (cutoff
The point) depends, of course, on the quality of the medium and the laser beam. 20% which is the range of non-recording beam output power
Keeping the value closer to the lower side of -30% gives enough room to perfectly match the width of the horizontal and vertical lines at the same exposure power.

The present invention has been described with respect to a portion of the heat-sensitive medium where recording is not performed and a specific portion where recording is performed. In this regard, it is understood that the non-recording and recording radiation beams are desirably applied on a pixel-by-pixel basis. That is, adjacent pixels are each exposed to non-recording radiation and recording radiation according to the present invention.

As described in detail above, implementing the present invention reduces the total energy requirement of the thermal image forming device,
A high quality image can be formed on the thermal medium. The present invention further facilitates the manufacture of a low cost thermal imaging device for forming high quality images on thermal media.

While the present invention has been described in terms of one or more preferred embodiments, those skilled in the art will appreciate that
It will be appreciated that the invention is not so limited. The various features and aspects of the invention described above can be utilized individually or together. Furthermore, while the present invention has been described in the context of a particular environment or implementation of the invention for a particular purpose, those skilled in the art will recognize that the utility of the invention is not limited thereto. It is understood that the invention can be beneficially used in many environments and embodiments. Therefore, the appended claims should be interpreted in light of the breadth and spirit of the invention described herein.

The features and aspects of the present invention are as follows.

1. A method for recording an image on a heat-sensitive medium 255, comprising a single radiation transmitter 2 in a first part of the medium.
Applying radiation from 05 and heating the medium to a first temperature;
Applying a radiation from a single radiant emitter to a second portion of the medium different from the first portion to heat the medium to a second temperature and record an image; The method wherein the medium is below a threshold temperature at which an image is recorded and the second temperature is equal to or above the threshold temperature.

[0062] 2. The method of claim 1, wherein the radiation from the single radiation transmitter is continuously applied to the medium.

3. Recording an image by applying radiation to a first portion of the media to heat the media to a first temperature and applying radiation to a second portion of the media to heat the media to a second temperature; 2. The method according to 1 above.

4. 4. The method of claim 3, wherein the first portion of the media is disposed proximate the second portion of the media.

5. 4. The method of claim 3, wherein the first portion of the media and the second portion of the media are adjacent.

6. The method of claim 3, wherein the second portion of the medium is recorded and the first portion of the medium is not recorded.

7. Radiation for heating the medium to a first temperature is performed at a first output power, and radiation for heating the medium to a second temperature and recording on the medium is different from the first output power. The method of claim 1, wherein the method is performed at output power.

8. A modulator for modulating the radiation, outputting radiation having a first output power onto the medium, controlling the modulator to heat the medium to a first temperature, and providing a second output; The method of claim 1, further comprising the step of outputting powered radiation to control the modulator to heat the medium to a second temperature.

9. An image generation device for recording an image on a thermal medium 255, comprising: a single radiation source 205 configured to generate and transmit radiation; and a first output power that modulates the transmitted radiation. A modulator 215 operable in a first mode for forming an output radiation having a first mode and a second mode for modulating the emitted radiation to form an output radiation beam having a second output power; Operating in a mode to heat the medium to a first temperature below a threshold temperature at which the medium records an image, and operating in a second mode to heat the medium to a second temperature at least equal to the threshold temperature. A recording device comprising a controller for controlling the modulator to record an image thereon.

10. The apparatus of claim 9, wherein the first output power is different from the second power.

11. The single radiation source is further configured to emit radiation continuously over the medium, and the controller further controls the modulator to switch between the first and second modes of operation to provide continuous emission. 10. The method of claim 9, wherein the emitted radiation is configured to switch between a first output power and a second output power.

12. In a first mode of operation, an output radiation beam of a first power impinges on a first portion of the medium, and in a second mode of operation, an output radiation beam of a second power impinges on a second portion of the medium. 10. The apparatus according to the above 9, wherein the image is recorded by using

13. The apparatus of claim 12, wherein the first and second portions of the medium do not overlap each other.

14. An optical scanning device 240 configured to scan the output radiation beam on the medium;
The controller controls the modulator so that when the modulator is operating in the first mode, the output radiation beam is scanned by the optical scanning device on the unrecorded first portion of the medium, and the modulator is moved to the second mode. Apparatus according to claim 9, wherein the output radiation beam is scanned by an optical scanning device on the recorded second portion of the medium when operating in the second mode.

[Brief description of the drawings]

FIG. 1 is an image forming apparatus of the present invention.

FIG. 2 shows a multi-beam imager with a directly modulatable radiation source according to the invention.

FIG. 3 is a schematic block diagram of the control device shown in FIG. 1;

FIG. 4 shows a non-recording portion and a recording portion (A) of a medium on which a positive image is created according to the present invention, and a non-recording portion and a recording portion (B) of a medium on which a screw image is created according to the present invention.

FIG. 5 tabulates the required recording beams at different non-recording beam output power levels.

[Explanation of symbols]

 205 Radiation oscillator 210 Condenser lens 215 Modulator 255 Heat medium 310 Controller

Claims (2)

[Claims] 1. A method for recording an image on a heat-sensitive medium, comprising applying radiation from a single radiant emitter to a first portion of the medium to heat the medium to a first temperature; Applying a radiation from a single radiant emitter to a second portion different from the first portion to heat the medium to a second temperature and record an image, wherein the first temperature is The method wherein the medium is below a threshold temperature for recording an image, and the second temperature is equal to or above the threshold temperature. 2. An image generating apparatus for recording an image on a thermal medium, comprising: a single radiation source configured to generate and transmit radiation; A modulator operable in a first mode for forming an output radiation having an output power of, and a second mode for modulating the emitted radiation to form an output radiation beam having a second output power; Operating in a first mode to heat the medium to a first temperature below a threshold temperature at which the medium records an image, and operating in a second mode to heat the medium to a second temperature at least equal to the threshold temperature. A recording device comprising a controller for controlling the modulator to record an image thereon.